#include<stdio.h>
int Sum(int n,int a,int k);
int main()
{
	int n,a,k,s;
	scanf("%d%d%d",&n,&a,&k);
	s=Sum(n,a,k);
	if(n>1)
	printf("%d",s);
	return 0;
}
int Sum(int n,int a,int k)
{
	if(n<=1||k>=100||a<=1||k<=1)
	printf("Wrong Number");
	else if(n>2)
	return k+Sum(n-1,a,k);
	else if(n==2)
	return a+k;
}

